Non-ideal Interaction Research Articles

Phase Equilibria of Sub-Neptunes and Super-Earths

We investigate the consequences of nonideal chemical interaction between silicate and overlying hydrogen-rich envelopes for rocky planets using basic tenets of phase equilibria. Based on our current understanding of the temperature and pressure conditions for complete miscibility of silicate and hydrogen, we find that the silicate-hydrogen binary solvus will dictate the nature of atmospheres and internal layering in rocky planets that garnered H2-rich primary atmospheres. The temperatures at the surfaces of supercritical magma oceans will correspond to the silicate-hydrogen solvus. As a result, the radial positions of supercritical magma ocean–atmosphere interfaces, rather than their temperatures and pressures, should reflect the thermal states of these planets. The conditions prescribed by the solvus influence the structure of the atmosphere, and thus the transit radii of sub-Neptunes. Separation of iron-rich metal to form metal cores in sub-Neptunes and super-Earths is not assured due to prospects for neutral buoyancy of metal in silicate melt induced by dissolution of H, Si, and O in the metal at high temperatures.

Theoretical concept of error-rejecting entanglement purification of quantum-dots electronic spins in single-sided optical microcavity

We use the quantum-dots (QD) coupled with single-sided microcavities system to construct the error-rejecting controlled not (CNOT) gate of electronic spins system in QD; We have designed an error-rejecting entanglement purification protocol (EPP) of electronic spins system in QD by using the error-rejecting CNOT gate and unitary operation. It can extract the high entanglement from the mixed entanglement states of the electronic spins with low entangled states. This EPP can eliminate the operation errors caused by the nonideal interaction between photons and QD coupled with optical microcavities system, and improve the fidelity of the EPP through iteration. Our scheme is more practical in future long-distance quantum communications, especially providing significant benefits for solving decoherence problems in quantum networks and quantum repeaters.

Modeling diffusion in ionic, crystalline solids with internal stress gradients

Intracrystalline diffusion is an invaluable tool for estimating timescales of geological events. Diffusion is typically modeled using gradients in chemical potential caused by variations in composition. However, chemical potential is derived for uniform pressure and temperature conditions and therefore cannot be used to model diffusion when there are gradients in stress. Internal stress variations in minerals will create gradients in strain energy which, in addition to gradients in composition, will drive diffusion. Consequently, it is necessary to have a method that incorporates stress variations into diffusion models.To address this issue, we have derived a flux expression that allows diffusion to be modeled in ionic, crystalline solids under arbitrary stress states. Our approach is consistent with standard petrological methods but instead utilizes gradients in a thermodynamic potential called “relative chemical potential.” Relative chemical potential accounts for the lattice constraint in crystalline solids by quantifying changes in free energy due to the exchanges of constituents on lattice sites under arbitrary stress conditions. Consequently, gradients in relative chemical potential can be used to model diffusion when pressure is not uniform (i.e., under conditions of non-hydrostatic stress).We apply our derivation to the common quaternary garnet solid solution almandine–pyrope–grossular–spessartine. The rates and directions of divalent cation diffusion in response to stress are determined by endmember molar volumes or lattice parameters, elastic moduli, and non-ideal activity interaction parameters. Our results predict that internal stress variations of one hundred MPa or more are required to shift garnet compositions by at least a few hundredths of a mole fraction. Mineral inclusions in garnet present a potential environment to test and apply our stress-driven diffusion approach, as stress variations ranging from hundreds of MPa to GPa-level are observed or predicted around such inclusions. The ability to model stress-induced diffusion may provide new information about the magnitudes of both intracrystalline stresses and the timescales during which they occurred, imparting a better understanding of large-scale tectono-metamorphic processes.

Competitive Interactions Between Microbial Siderophores and Humic-Like Binding Sites in European Shelf Sea Waters

Siderophores are low molecular weight high affinity iron chelates found at low concentrations in seawater. In this study we determined the total concentrations and identities of siderophores in extracts isolated from a shelf sea environment on the Northwest European shelf by high performance liquid chromatography coupled to high resolution inductively coupled plasma mass spectrometry (ICP-MS) in parallel to high resolution electrospray ionisation mass spectrometry (ESI-MS). We identified a total of 24 different siderophores in our samples via metal isotope profiling of masses detected by ESI-MS. Twenty three of the identified siderophores could be assigned to three siderophore families – ferrioxamines, amphibactins and marinobactins. In contrast, only 12 peaks could be resolved in iron chromatograms obtained via ICP-MS analysis. Comparison of results obtained by the two mass spectrometry detectors showed that neither method was able to detect and identify all siderophores present in the samples on its own. We assessed the impact of our observed total siderophore concentrations on iron speciation by calculating the distribution of iron species as a function of total siderophore concentrations at different iron concentrations representative of our study area. We considered competition for iron between siderophores, a humic like dissolved organic matter (DOM) fraction and hydroxide ions by combining an ion-pair model with a non-ideal competitive interaction (NICA)-Donnan model. We found that the overall impact of siderophores on iron biogeochemistry is low at concentrations of siderophore <100 pmol L-1, and that the dominant iron species present at siderophore concentrations of the order of a few tens of pmol L-1 will be iron bound to the humic like DOM fraction. Furthermore the heterogeneity of binding sites in the humic like DOM fraction means that other binding sites present in organic matter could be effective competitors for siderophores, especially at low iron concentrations. Our findings highlight the importance of binding site heterogeneity when considering the influence of different iron binding groups on iron speciation in the marine environment.

A single-phase diffusion model for gas injection in tight oil reservoirs

This paper presents a mechanistic simulation study of one-dimensional multicomponent diffusion when the miscible injectant diffuses into a tight porous medium through the fracture/matrix interface with constant pore volume and temperature. The numerical implementation of diffusion based on the dusty gas model uses the fugacity gradient for each component in the mixture as the driving force to the diffusive flux. The Peng-Robinson equation of state is used to model the non-ideal interactions among components in the miscible diffusive process. Phase stability analysis by minimization of the Helmholtz free energy is performed for each grid block at every time step to ensure that mixtures are single-phase fluids throughout the simulation.The main novelty of this paper lies in the diffusion model and its theoretical analysis, in which the fluid non-ideality affects the multicomponent diffusion through two pathways: the fugacity coefficients and the volume change on mixing that causes local pressures to change under ultra-low permeability in tight porous media. Previous studies based on the Maxwell-Stefan model did not consider the latter pathway, while others based on Fick's law are even more simplistic by not considering the non-ideal chemical potential.Analysis in this research showed that the Maxwell-Stefan model was inconsistent with its own assumption of no pressure gradient when non-ideal mixing was considered for tight reservoirs. The dusty gas model does not have this issue because it allows for pressure gradients to drive mass transfer by Knudsen diffusion. The non-ideal interaction of components should be properly characterized and utilized to enhance the early-time flux through the fracture/matrix interface in miscible gas injection into a tight reservoir. Case studies show that the volume change on mixing may substantially increase local pressures and the rate of mass transfer in tight reservoirs. Also, the fugacity coefficients of oil components at infinite dilution in the solvent had a major influence on the rate of diffusion. These two factors highlight the importance of properly characterizing reservoir fluids through an equation of state.

Development of a novel monitoring system for the in-process characterisation of the machine and tooling effects in Inertia Friction Welding (IFW)

Inertia Friction Welding (IFW) is commonly approached by considering ideal conditions in which the two workpieces are in perfect contact, subjected to the nominal loads and the machine reacts ideally to the process loads. These conditions, however, are not representative of a real weld, where fixturing issues, non-ideal interaction between the workpieces and compliance of the system under the process loads could significantly affect the quality and the repeatability of the weld. To fill this research gap, a novel monitoring system able to collect in-process data and a methodology for their analysis was developed. A set of rundown tests and steel w elds were performed on an industrial inertia welder to validate the rig. Then, the data extracted were used to study the interaction conditions between the spindle and fixture side of the machine and build dynamics models to understand the physical implication of specific events connected to the impact at part contact and the flywheel deceleration. The results showed a significant influence of the machine in the alignment of the workpieces, with the runout between spindle and fixture that became larger and irregular during welding when the workpieces interact in non-ideal conditions. The quantitative comparison between the runout magnitude of rundown tests and welds showed an increase of more than four times that can be justified with the compliance of the machine, in which the spindle bearings representing the weakest element. The comparison of the outputs of the different sensors installed allowed to obtain, for the first time, a holistic view of the macroscopic phenomena occurring during the welding phase and observe how these could affect the final weld geometry and the dynamically evolving thermo-mechanical conditions of the weld.

Distribution of Cholesterol in Asymmetric Membranes Driven by Composition and Differential Stress

Many biological membranes, in particular plasma membranes of eukaryotic cells, are asymmetric, which means that their two leaflets differ from one another. This asymmetry can arise in a number of ways, and we focus on the following two: a difference in lipid type, and a difference in lateral stress, arising from overfilling one leaflet with respect to the other. The two ways presuppose that lipids, once put in a given leaflet, stay in that leaflet. This is true for most phospholipids, but not for cholesterol, which transitions rapidly enough between leaflets so that its distribution is determined by chemical equilibrium. Given that compressive stress presumably excludes cholesterol from a leaflet, while preferential partitioning can draw it into a leaflet, this poses the question of how these two types of asymmetry cooperatively affect the distribution of cholesterol. Using a highly coarse-grained membrane model, we investigate how these two driving forces play against each other until cholesterol's chemical potential is equilibrated. We also model this system theoretically using two coupled elastic sheets whose composition degrees of freedom are described by a simple lattice gas model with a non-ideal mixing parameter χ. We find that the results from the simulations agree with the predictions if we allow for just one free parameter, which empirically determines how χ relates to the non-ideal interaction energy between cholesterol and lipids in either of the two leaflets. We anticipate that our simple model can help shed light on the longstanding puzzle of how cholesterol distributes in cellular plasma membranes, and whether the resulting equilibrium puts them under differential stress.

Unidirectional transmission of single photons under nonideal chiral photon-atom interactions

Single-photon transport in non-ideal chiral photon-atom interaction structures generally contains information backflow and thus limits the capabilities to transfer information between distant emitters in cascaded quantum networks. Here, in the non-ideal chiral case, a V -type atom coupled to a waveguide is proposed to realize completely unidirectional transmission of the single photons in a superposition state of different frequencies. A microwave field is introduced to drive the two excited states of the atom and results in photon conversion between two transitions. By adjusting the Rabi frequency and the phase of the external driving field, the transport behaviors of incident photons with specific frequencies can be optimized to complete transmission or reflection. Based on the constructive interferences between photons from different traveling paths, the transmission probabilities of the specific-frequency photons could be enhanced. Due to photon conversions with compensating the dissipations and ensuring the complete destructive interference, the ideal unidirectional transmission contrast can be maintained to 1, even when the atom has dissipations into the non-waveguide modes.

Experiments on water vapour condensation within supersonic nozzle flow generated by an impulse tunnel

An impulse facility for analysis of water vapour nozzle flows using both shock tunnel and Ludwieg tube operating modes has been developed and tested at the University of Southern Queensland. Unique high-speed flow visualisation of the water vapour condensation shock has been acquired in the throat region of a nominally two-dimensional convergent-divergent nozzle with a 120 mm2 throat area. This paper presents the facility performance and the time-resolved visualisation results for the nozzle flow, and the results are analysed with the aid of image post-processing tools and quasi-one-dimensional (Q1D) thermodynamic calculations. The experiments have produced qualitative and quantitative data on the flow conditions at four different relative humidity values from 25% to 100%, and over a range of nozzle supply temperatures between 293 K and 343 K. The direct measurement of the pressures and wave speeds within the tunnel resulted in a good agreement with the ideal gas Q1D calculations, particularly for the first incident shocks and expansion waves. Differences progressively increased with the number of reflections, due to the effect of viscous dissipation and the non-ideal end-wall interaction caused by the presence of the nozzle inlet. Moreover, flow visualizations of the location and orientation of both the weak disturbance waves and the condensation shock enabled the investigation of the supersonic water vapour condensation within the nozzle of this impulse facility. Based on these measurements, the nozzle flow downstream of the condensation shock was demonstrated to have a lower Mach number relative to the dry nitrogen flow case. This phenomenon is due to the phase change heat release, which appeared to be more significant when the condensation shock intensity was higher. Although further development of the apparatus is possible, the impulse test-rig configuration that we have developed permits a relatively high flow rate of test gas for a short period of time, leading to significantly reduced operating expenses relative to a continuous flow facility with the same mass flow rate. It is therefore suggested that future studies further improve and test the impulse facility techniques for studying condensation phenomena as a potential alternative to high-power, continuous flow facilities.

Theory of the electron-ion temperature relaxation rate spanning the hot solid metals and plasma phases.

We present a theory for the rate of energy exchange between electrons and ions-also known as the electron-ion coupling factor-in physical systems ranging from hot solid metals to plasmas, including liquid metals and warm dense matter. The paper provides the theoretical foundations of a recent work [J. Simoni and J. Daligault, Phys. Rev. Lett. 122, 205001 (2019)PRLTAO0031-900710.1103/PhysRevLett.122.205001], where first-principles quantum molecular dynamics calculations based on this theory were presented for representative materials and conditions. We first derive a general expression for the electron-ion coupling factor that includes self-consistently the quantum mechanical and statistical nature of electrons, the thermal and disorder effects, and the correlations between particles. The electron-ion coupling is related to the friction coefficients felt by individual ions due to their nonadiabatic interactions with the electrons. Each coefficient satisfies a Kubo relation given by the time integral of the autocorrelation function of the interaction force of an ion with the electrons. Exact properties and different representations of the general expressions are discussed. We then show that our theory reduces to well-known models in limiting cases. In particular, we show that it simplifies to the standard electron-phonon coupling formula in the limit of hot solids with lattice and electronic temperatures much greater than the Debye temperature, and that it extends the electron-phonon coupling formula beyond the harmonic phonon approximation. For plasmas, we show that the theory readily reduces to the well-known Spitzer formula in the hot plasma limit, to the Fermi "golden rule" formula in the limit of weak electron-ion interactions, and to other models proposed to go beyond the latter approximation. We explain that the electron-ion coupling is particularly well adapted to average atom models, which offer an effective way to include nonideal interaction effects to the standard models and at a much reduced computational cost in comparison to first-principles quantum molecular dynamics simulations.

A binary mixture of a biosurfactant and an ionic liquid surfactant as a green dispersant for oil spill remediation

Formulations based on conventional surfactants and organic solvents have been used as potential dispersants for oil-spill remediation. However, their toxicity restricts their usage in marine environments. As a low-toxicity alternative, in this article we report an oil dispersant based on a binary mixture of an ionic liquid surfactant, choline laurate ([Cho][Lau]), and a biosurfactant, lactonic sophorolipid. We investigated the micellar properties, including the critical micelle concentration, micellar interaction parameter (β), and activity coefficients (f1 and f2) for the mixed surfactant system. A non-ideal and synergistic interaction between [Cho][Lau] and lactonic sophorolipid was observed. A stable oil-in-water emulsion formed at an optimal ratio of 40:60 (w/w) of [Cho][Lau] and lactonic sophorolipid. At this ratio, a dispersion effectiveness of 83% was achieved with a dispersant-to-oil ratio of 1:25 (v/v). We observed the dispersed oil droplets with an optical microscope and evaluated their size using dynamic light scattering. The droplet size decreased with increasing dispersant-to-oil ratio. We also assessed the toxicity of the binary surfactant mixture in zebra fish (Danio rerio). Based on this assessment, the mixture can be classified as non-toxic. Therefore, the mixture of [Cho][Lau] and lactonic sophorolipid is a potential alternative to conventional toxic oil-spill dispersants.

Aggregation behavior and antimicrobial activity of a micellar system of binary ionic liquids

Ionic liquid (IL) surfactants have attracted great attention as potential alternatives to conventional surfactants because of their unique tailor-made physicochemical properties. However, in most cases, the aggregations formed by single IL surfactants in aqueous media are unstable, even when using a large amount of surfactant. To address this limitation, here we investigated the aggregation behavior of binary IL surfactant micelles composed of the ILs choline oleate ([Cho][Ol]) and choline laurate ([Cho][Lau]) in aqueous media using tensiometry and dynamic light scattering measurements. Micellar and interfacial parameters including critical micelle concentration (cmc), micellar interaction parameters (β), activity coefficients (f1 and f2), surface excess concentration (Гmax), minimum surface area per molecule (Amin), and the size of surfactant aggregates were studied. In addition, various thermodynamic parameters such as the Gibbs free energy of micellization (∆Gomic), standard Gibbs free energy of adsorption (∆Goad), molar free energy (Gmin), and the excess Gibbs free energy of micellization (ΔGex) were also evaluated. A non-ideal synergistic interaction was observed for the mixed IL surfactant system, which formed larger micelles (105–120 nm) compared with those formed with a single IL (86–102 nm). The formed micelles were found to be thermodynamically stable with regards to all the mole ratio of ILs system. The antimicrobial activity of the single as well of the mixed IL system against Gram-positive and -negative bacteria displayed a low toxicity profile that fell in the range of “practically harmless” (100–1000 mg L−1). The results suggested that the micellar system composed of mixed IL surfactants provides unique physical, chemical, and biological properties may offer novel opportunities for various applications such as oil dispersants.

Sommerfeld effect in an oscillator with a reciprocating mass

In this paper, the dynamics of a non-ideally driven single-degree-of-freedom vibrating system will be explored in detail. The objective is to describe Sommerfeld effect in a reciprocating system. As such, the concerned vibrating system comprises a reciprocating system with all components fully enclosed within a housing/foundation. The foundation is equipped with flexible mountings that are designed to contain and isolate any large amplitude vibrations. The assembly is devoid of any inertia forces arising due to rotational imbalances. As a result, all structural vibrations are caused due to a net unbalanced reciprocating mass only. As stated earlier, the mechanism is powered by a non-ideal drive. As a result, the non-ideal source-system interaction leads to the so-called Sommerfeld effect and the associated nonlinear jump phenomenon. For suitable component parameters, the nature of jump will be first investigated analytically. For a vibrating system, a non-ideal drive may inhibit smooth passages through resonance. Apart from sustainability issues, this may severely compromise a machine’s safety and reliability aspects. To that end, the power requirement conditions for smooth transition through resonance will be derived. It is to be noted that the analytical study will exclusively pertain to steady-state solutions. As such, to inspect the transient nature of the system dynamics, the non-ideal system will be modeled with the help of bond graphs. Additionally, the mechanism will also be assembled on MSC-Adams to confirm the responses obtained from the bond graph model. The simulated responses will then be used to verify the analytical predictions.

Camera-based window-opening estimation in a naturally ventilated office

ABSTRACTNaturally ventilated offices enable users to control their environment through the opening of windows. Whilst this level of control is welcomed by users, it creates risk in terms of energy performance, especially during the heating season. In older office buildings, facilities managers usually obtain energy information at the building level. They are often unaware or unable to respond to non-ideal facade interaction by users often as a result of poor environmental control provision. In the summer months, this may mean poor use of free cooling opportunities, whereas in the winter space heating may be wasteful. This paper describes a low-cost, camera-based system to diagnose automatically the status of each window (open or closed) in a facade. The system is shown to achieve a window status prediction accuracy level of 90–97% across both winter and summer test periods in a case study building. A number of limitations are discussed including winter daylight hours, the impact of rain, and the use of fixed camera locations and how these may be addressed. Options to use this window-opening information to engage with office users are explored.

Electrochemically Reversible Solubilization of Polycyclic Aromatic Hydrocarbons by Mixed Micelles Composed of Redox-active Cationic Surfactant and Conventional Nonionic Surfactant

Reduplicate utilization of surfactants is a key factor for Surfactant-Enhanced Remediation (SER) technology to reduce its high operation costs. In order to achieve the reuse of surfactants, this study attempted to construct a novel reversible solubilization system for SER. Three typical polycyclic aromatic hydrocarbons (PAHs) pyrene, phenanthrene, and acenaphthene were controllably solubilized and released by the mixed micelles composed of redox-active cationic surfactant (11-Ferrocenylundecyl) trimethylammoniunm bromide (FTMA) and conventional nonionic surfactant Tween80. Solubilization of PAHs is assumed to be controlled by changing the redox states of FTMA. Cyclic voltammograms tests of FTMA showed the oxidation and reduction potential were 0.4570 and 0.4068 V, respectively, and the peak currents ratio of FTMA and FTMA+ was 1.26, verified that FTMA possesses electrochemically reversible property. In FTMA-Tween80 mixed solutions, CMC values demonstrated the nonideal interaction between the two surfactants and the interaction parameters (β) was -5.5296 when the mass ratio was FTMA:Tween80 = 2:8. Due to the synergistic solubilization effect, the apparent water solubilities of PAHs were significantly enhanced by the mixed surfactant, and they were much higher than those in single surfactant. After oxidation, more than 50% of the PAHs in mixed micelles could be released, the cumulative release efficiency of selected PAHs followed the order of pyrene > pherantherene > acenaphthene. Briefly, such results in this article provide a facile method to meliorate the SER technology.

Passively-switched energy harvester for increased operational range

This paper presents modeling and experimental validation of a new type of vibrational energy harvester that passively switches between two dynamical modes of operation to expand the range of driving frequencies and accelerations over which the harvester effectively extracts power. In both modes, a driving beam with a low resonant frequency couples into ambient vibrations and transfers their energy to a generating beam that has a higher resonant frequency. The generating beam converts the mechanical power into electrical power. In coupled-motion mode, the driving beam bounces off the generating beam. In plucked mode, the driving beam deflects the generating beam until the driving beam passes from above the generating beam to below it or vice versa. Analytical system models are implemented numerically in the time domain for driving frequencies of 3 Hz to 27 Hz and accelerations from 0.1 g to 2.6 g, and both system dynamics and output power are predicted. A corresponding switched-dynamics harvester is tested experimentally, and its voltage, power, and dynamics are recorded. In both models and experiments, coupled-motion harvesting is observed at lower accelerations, whereas plucked harvesting and/or mixed mode harvesting are observed at higher accelerations. As expected, plucked harvesting outputs greater power than coupled-motion harvesting in both simulations and experiments. The predicted (1.8 mW) and measured (1.56 mW) maximum average power levels are similar under measured conditions at 0.5 g. When the system switches to dynamics that are characteristic of higher frequencies, the difference between predicted and measured power levels is more pronounced due to non-ideal mechanical interaction between the beams’ tips. Despite the beams’ non-ideal interactions, switched-dynamics operation increases the harvester’s operating range.

Characterization and Solution Structure of Mouse Myristoylated Methionine Sulfoxide Reductase A

Methionine sulfoxide reductase A is an essential enzyme in the antioxidant system which scavenges reactive oxygen species through cyclic oxidation and reduction of methionine and methionine sulfoxide. The cytosolic form of the enzyme is myristoylated, but it is not known to translocate to membranes, and the function of myristoylation is not established. We compared the biochemical and biophysical properties of myristoylated and nonmyristoylated mouse methionine sulfoxide reductase A. These were almost identical for both forms of the enzyme, except that the myristoylated form reduced methionine sulfoxide in protein much faster than the nonmyristoylated form. We determined the solution structure of the myristoylated protein and found that the myristoyl group lies in a relatively surface exposed "myristoyl nest." We propose that this structure functions to enhance protein-protein interaction.

Ion size effects on electric double layers and ionic transport through ion-exchange membrane systems

The density function theory is used to study the density profiles and the transport properties of an ion-exchange membrane system submitted to an electric potential drop. As the ionic density increases, hard sphere interaction between ions becomes dominant and the ion size must be taken into account. The results show that the density distribution and the transport properties depend on the bulk electrolyte density. At equilibrium the charge inside the electric double layer (EDL) adjacent to the membrane decreases and the membrane electric potential increases as the bulk density increases. For high bulk density of unsymmetric electrolyte, secondary charge layers are observed inside the EDL. In the membrane the anion-density-to-bulk-density ratio increases when the bulk density increases from small to moderate values owing to the membrane potential increase. But it decreases abruptly at high bulk density values owing to the increase of the non-ideal electrostatic interaction. At a given electric potential drop, the current/voltage curves follow the variation of this ratio with respect to the bulk density at equilibrium. As the current density approaches the limiting one, the amplitude of the secondary charge layers decreases and the EDL thickness increases.

Non-local kinetic theory of inhomogeneous liquid mixtures

In this work we investigate the dynamical properties of a mixture of mutually interacting spherical molecules of different masses and sizes. From an analysis of the microscopic laws governing the motion of the molecules we derive a set of non-local self-consistent equations for the singlet phase-space distribution functions. The theory is shown to reproduce the hydrodynamic equations for the densities of each species, the total momentum and the local temperature. The non-ideal gas interaction term is separated into a contribution due to the repulsive part, which is treated by means of the revised Enskog theory for hard spheres, and an attractive contribution treated within the random phase approximation. The present formulation accounts for the effects of the density and velocity inhomogeneities, both on the thermodynamic and transport properties of the fluid. In a special limit, where one species is massive and diluted, the theory leads to a description that is formally identical to the dynamic density functional equation governing the time evolution of a colloidal system. The derivation also determines the dependence of the friction coefficient, appearing in the dynamic density functional theory, on the microscopic parameters of the solvent. However, the predicted value takes into account only the collisional contributions to the friction and not the Stokes friction of hydrodynamic origin, suggesting that velocity correlations should be incorporated in a more complete treatment.

Seeing Chekhov: Life and Art by Michael C. Finke

306 Reviews of self-willswith theirhidden motives and subconscious drives-makes for a fasci nating reading, reminiscent of the illuminating finale of a detective novel where all the pieces of a jigsaw puzzle are put together by a skilful sleuth. Using a 'descend ing'metaphor, Young's book brings tomind Eric Berne's best-selling Games People Play: The Psychology ofHuman Relationships (Harmondsworth: Penguin, I964) by demonstrating the theatre of lifebehind Dostoevsky's characters' multi-levelled in teractions. However, while Berne's book results in schematizing and simplification of human interactions for the general audience, Young's work, with itsmeticulous attention to detail and penetrating insights, sustains the highest level of scholarly research and inscribes human psychology into a complex literaryuniverse, studying simultaneously the superimposed scripts of the characters and theway Dostoevsky's fiction refracts these human interactions and is shaped by them. Feeling remarkably at ease with thevast body of existing research,Young both com plements and challenges other scholars, including Bakhtin. Thus she demonstrates that 'by identifying the scripting strategies [. . .] the reader is able to distinguish between degrees of ideal and non-ideal dialogic interaction, an issue which Bakhtin in general fails to address' (p. 25). Like Harriet Murav inHoly Foolishness: Dosto evsky'sNovels & thePoetics ofCultural Critique (Stanford, CA: Stanford University Press, 1992), Young exposes thedestructive and dark features of the carnivalesque in contrast toBakhtin's perception of itas joyful and life-affirming. Of course, one may not necessarily agree with all ofYoung's conclusions, but then it is hardly possible to 'resolve' the enigma of Dostoevsky's fiction,which forever escapes finalization. Thus, forexample, Young suggests that it isperhaps 'the overt implication of the reader in theprocess of thecharacters' coming intobeing' (p. I84) thatmakes The Idiot such amemorable novel. However, formany the effect may be confined just to the images as such: the striking and overpowering image ofNastas'ia Filippovna or, as forFazil' Iskander, of Prince Myshkin: 'It is such people that are most striking:with a beautiful soul and damaged mental capacities, unable to pro cess their personal interests logically', Iskander writes (E Iskander, 'Ponemnogu o mnogom', Novyi mir, 10 (2000), I I6-48 (p. I33)). Iwould highly recommend Young's engaging work to all thosewho enjoy both the challenge and the stimulus ofDostoevsky's ceuvre.The book could benefit from an index,which scholars would certainly findhelpful; this is something that could be incorporated in a second edition. UNIVERSITY OF BATH OLGA TABACHNIKOVA Seeing Chekhov: Life and Art By MICHAEL C. FINKE. Ithaca, NY, and London: CornellUniversityPress. 2005. xi+237pp. $29.95. ISBN978-o-80I4-43I5-2. The 2004 centenary of Chekhov's death has ensured that for some years to come monographs and collections of conference papers will continue to be published, in a desperate attempt to findmore material on Chekhov or new frameworks intowhich he can be placed. Given that there are only fourmajor plays and about two dozen stories onwhich Chekhov's reputation rests,critics are forced touse hindsight or self persuasion to see genius inhis early hack work or his firstattempts at constructing a tragicomedy.With theopening ofRussian archives in I990, all Chekhov's lettersand the immense correspondence directed at or about him by his contemporaries have come into the public domain, and this has resulted in amass of biographical detail thatcan only be reassembled indifferentpatterns. Michael Finke's monograph, ifnot an outstanding triumph, is quite an achieve ment, given these difficulties.This book agglomerates a number of articles, theearliest MLR, 103. 1, 2oo8 307 dating from I993, and by creating continuity,chopping out theduplication, and bring ing in the leitmotifof the title as a conceit of both authors, Chekhov and Finke, as unseen seerswho unwittingly show themselves when theyhide, succeeds inmaking a genuinely readable critique of Chekhov. Above all, Finke writes very cogently, so thatevenwhen his assertions and judgements are questionable he retains our respect and interest. Sometimes he takes Chekhov, a man prone to self-contradiction, too much at face value. One cannot make Chekhov's autobiographophobia a premiss for a critique, when much of the evidence points in the opposite direction. The use of facts,even names, fromChekhov's private life, well known to literarycircles, in stories such...